The invention relates to an apparatus for pressing a flattened book casing against the adhesive-coated outside surfaces of a book block to be encased in a casing-in machine. An apparatus comprises two pressing-on rollers that are positioned opposite each other in a pressing-on region of a pressing-on device, which is driven synchronously with a conveyor, wherein these rollers respectively press one book cover of the book casing against one adhesive-coated outside surface of a book block, positioned on a vertically upward moving saddle plate of a circulating conveyor.
The visual attractiveness of a book depends, in part, on the quality of the work when encasing a book block in a book casing. For that reason, a precise joining of book block and book casing is therefore necessary not only for high-quality books, but also to ensure that the outside edges of both parts extend visibly parallel to each other and that a uniform spacing is visible between the parallel outside edges. In addition, the book covers of a book casing must rest with the complete surface and without raised areas on the book block and/or must be glued on the inside to the end papers, so that no folds can form and the outside edges extend parallel to each other, wherein the back insert or the back lining fits against the book block spine of a closed book.
The typical steps of this process are described, for example, in European Patent Document 1 072 436 A1 (Jan. 31, 2001). However, the described process has the disadvantage that the movement course for the pressing-on device is fixedly determined by a mechanically acting control cam of a control element and can be changed only if the control element is replaced. In practical operations, a single control element is therefore used which is suitable for formats up to the largest one. Furthermore, a joint electric motor is used for driving the book block conveyor and the pressing-on device, which results in long movement paths and/or high acceleration forces for the pressing-on device, even with smaller book formats.
Also, of high importance is the distance traveled by the pressing-on device along the synchronizing section, between the book block spine and the back insert in a state where the book casing rests unsupported on a casing support and/or the pressing-down rollers approximately make contact with the surface of the book casing (at the so-called attachment point). The attachment point is primarily determined by the thickness and/or the cross-sectional shape of a book block spine.
Until now, the length of the synchronizing section was kept constant for all book formats.
If the pressing-on device is located on the synchronizing section, the pressing-on rollers initially lift off the book casing and then return to it once the pressing-on device reaches the end of the synchronizing section. At the start of the production, attention must be paid to ensure that the movement of the pressing-on rollers on the pressing-on device is adapted to the supplied book casing, corresponding to the desired fold and/or joint of a book. It is therefore necessary to ensure at the start of the production that the attachment point for the pressing-on device can be set and/or changed by adjusting the control element. This operation has until now been possible only if the apparatus is stopped, for example by adjusting the mechanically effective control element manually or with a specialized gear.